Precautions When Wiring To The Output Units - Omron NX-ID3343 User Manual

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Precautions when Wiring to the Output Units

Output Short-circuit Protection
If a load connected to the output terminals is short-circuited, output components and printed circuit
boards may be damaged. To guard against this, use the NX Units with load short-circuit protection.
When using the NX Units without load short-circuit protection, incorporate a protective fuse in the exter-
nal circuit. Use a fuse with a capacity of around twice the rated output.
Inrush Current
When connecting a transistor to an output device with a high inrush current (such as an incandescent
lamp), steps must be taken to avoid damage to the output transistor.
Use either of the following methods to reduce the inrush current.
 Countermeasure 1
Draw about 1/3 of the current consumed by the load.
When I/O power is supplied from the NX bus, the method is as shown in the following figure.
NPN type
Communications
Coupler Unit or
Additional I/O Power
Supply Unit
Transistor Output Unit
When I/O power is supplied from an external source, the method is as shown in the following figure.
NPN type
Transistor Output Unit
NX-series Digital I/O Unit User's Manual (W521)
IOV
IOG
IOV
L
OUT
IOG
OUT
L
+
R
COM
4 Installation and Wiring
PNP type
Communications
IOV
Coupler Unit or
Additional I/O Power
IOG
Supply Unit
IOV
OUT
Transistor Output Unit
IOG
PNP type
COM
Transistor Output Unit
OUT
4
L
+
R
L
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